In the inspection object having the wires arranged in the matrix in the x-axis direction and the y-axis direction formed on an ITO film referred to as the touch panel (or a touch screen or a touch display), conventionally, conduction of each wire and a short-circuit between adjacent wires are inspected by bringing each contactor (or needle-shaped conductive probe) into contact with respective one of the wires arranged in the x-axis direction and the y-axis direction.
However, in the method of performing the inspection by bringing each contactor into contact with respective one of the wires as described above, there is no stability between the wire formed on the ITO film and the contactor, and the instability of contact resistance due to the oxide film causes inaccurate measurement of the electrical characteristic, which is problematic. Moreover, since the contactor is pressure-welded with the wire as the inspection object, there is such a problem that a dent or damage is formed due to the contact of the contactor with the wire.
On the other hand, as disclosed in Japanese Patent Application Laid Open No. 2005-274225, there is also proposed an inspection technology of accurately inspecting the electrical characteristics such as a resistance value of the touch panel as a whole, in which a predetermined touch input position on the touch panel assembled can be accurately detected. As described above, there is disclosed a technology of inspecting the electrical characteristics of the functions of the touch panel assembled.
There is also another technology, other than the technology disclosed in Japanese Patent Application Laid Open No. 2005-274225, in which due to the arrangement of the touch panel for crossing x-axis wires and y-axis wires, the contactor is brought into contact with an intersection point at which the x-axis wire crosses y-axis wire, an inspection signal is supplied from each of the x-axis wire and y-axis wire, and the quality of the x-axis wire and y-axis wire is determined from a detection signal from the contactor.
In the inspection method as described above, however, the inspection needs to be performed the number of times indicated by the multiplication of the total number of the x-axis wires and the total number of the y-axis wires, and there is such a problem that a long inspection time is required.
Recently, there has been a rising demand for productivity growth, and it is thus necessary to reduce a tact time and to complete the inspection in a short time. Particularly in recent years, the touch panel has been used as an inputting device which allows multi-touch, and thus, the entire panel surface needs to be accurately covered with the wires. Therefore, there is a rising demand to detect and determine not only the conduction and short-circuit of the wires but also the thickening and thinning of the wires.